Lululemon Athletica claims in its lawsuit filed in the U.S. District Court for the Central District of California that Costco has “unlawfully traded” on its reputation, goodwill and sweat equity by selling unauthorized and unlicensed apparel that uses knockoff, infringing versions of its patents.

Cheaper look-alikes have been around for years, but social media has made them more popular. Dupes can move into shaky legal territory if concerns arise around consumer confusion or patented designs.

Costco’s viral jogger moment is just the latest example of how deep dupe culture runs and how much trust the brand has earned with shoppers. While the company faces a legal battle over allegedly copying some of Lululemon’s popular products, these Vuori lookalike joggers are gaining traction without sparking that same backlash...at least for now.